scholarly journals Correlation between Tribological Properties and the Quantified Structural Changes of Lysozyme on Poly (2-hydroxyethyl methacrylate) Contact Lens

Polymers ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 1639
Author(s):  
You-Cheng Chang ◽  
Chen-Ying Su ◽  
Chia-Hua Chang ◽  
Hsu-Wei Fang ◽  
Yang Wei
Keyword(s):  
Friction Coefficient ◽  
Protein Interactions ◽  
Contact Lens ◽  
Structural Changes ◽  
Hydroxyethyl Methacrylate ◽  
Tear Proteins ◽  
Adsorbed Protein ◽  
Adsorbed Proteins ◽  
Lens Material

The ocular discomfort is the leading cause of contact lens wear discontinuation. Although the tear proteins as a lubricant might improve contact lens adaptation, some in vitro studies suggested that the amount of adsorbed proteins could not simply explain the lubricating performance of adsorbed proteins. The purpose of this study was to quantify the structural changes and corresponding ocular lubricating properties of adsorbed protein on a conventional contact lens material, poly (2-hydroxyethyl methacrylate) (pHEMA). The adsorption behaviors of lysozyme on pHEMA were determined by the combined effects of protein–surface and protein–protein interactions. Lysozyme, the most abundant protein in tear, was first adsorbed onto the pHEMA surface under widely varying protein solution concentrations to saturate the surface, with the areal density of the adsorbed protein presenting different protein–protein effects within the layer. These values were correlated with the measured secondary structures, and corresponding friction coefficient of the adsorbed and protein covered lens surface, respectively. The decreased friction coefficient value was an indicator of the lubricated surfaces with improved adaptation. Our results indicate that the protein–protein effects help stabilize the structure of adsorbed lysozyme on pHEMA with the raised friction coefficient measured critical for the innovation of contact lens material designs with improved adaptation.

In Vitro Adsorption of Tear Proteins to Hydroxyethyl Methacrylate-Based Contact Lens Materials

2009 ◽  
Vol 35 (6) ◽  
pp. 320-328 ◽  
Author(s):  
Fiona P. Carney ◽  
Carol A. Morris ◽  
Bruce Milthorpe ◽  
Judith L. Flanagan ◽  
Mark D.P. Willcox
Keyword(s):  
Contact Lens ◽  
Hydroxyethyl Methacrylate ◽  
Tear Proteins

Effect of multipurpose solutions for contact lens care on the in vitro drug-induced spoliation of poly(2-hydroxyethyl methacrylate) in simulated aqueous humour

2005 ◽  
Vol 28 (1) ◽  
pp. 21-28 ◽  
Author(s):  
Traian V. Chirila ◽  
David A. Morrison ◽  
Zoya Gridneva ◽  
Danielle Meyrick ◽  
Celia R. Hicks ◽  
...  
Keyword(s):  
Contact Lens ◽  
Aqueous Humour ◽  
Hydroxyethyl Methacrylate ◽  
Drug Induced

scholarly journals The Bio-Tribological Effect of Poly-Gamma-Glutamic Acid in the Lysozyme-Ionic Contact Lens System

Polymers ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 156
Author(s):  
Chen-Ying Su ◽  
Lung-Kun Yeh ◽  
Chi-Chun Lai ◽  
Mihaela Dubuisson ◽  
Yi-Fei Tsao ◽  
...  
Keyword(s):  
Friction Coefficient ◽  
Glutamic Acid ◽  
Contact Lens ◽  
Contact Lenses ◽  
Lens System ◽  
Friction Testing ◽  
Lubricating Property ◽  
Velocity Variations

Feeling comfortable is an important issue for contact lens wearers as contact lenses are worn for an extensive period of time. It has been shown that the in vitro friction coefficient of contact lenses is correlated to the degree of in vivo comfort, thus many studies focus on establishing friction testing methods for investigating the friction coefficient of contact lenses or contact lens care solution. We have previously demonstrated the lubricating property of poly-gamma-glutamic acid (γ-PGA)-containing care solution, and it could reduce the high friction coefficient caused by lysozyme. However, the mechanism of how γ-PGA-containing care solution reduces the lysozyme-induced friction coefficient of contact lenses is unclear. We investigated the bio-tribological effect of γ-PGA on ionic contact lenses in the presence of lysozyme by testing load and velocity variations. The ability to remove lysozyme deposition by γ-PGA and viscosity analysis of γ-PGA-containing care solutions were also investigated to understand the potential mechanism. Our results showed that the friction coefficient of γ-PGA-containing care solution with lysozyme was the lowest in both load and velocity variations, and γ-PGA functions distinctly in the lysozyme-ionic contact lens system. We proposed a model of how γ-PGA could reduce the friction coefficient in these two conditions.

scholarly journals Quantify the Protein–Protein Interaction Effects on Adsorption Related Lubricating Behaviors of α-Amylase on a Glass Surface

Polymers ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 1658
Author(s):  
Nareshkumar Baskaran ◽  
You-Cheng Chang ◽  
Chia-Hua Chang ◽  
Shun-Kai Hung ◽  
Chuan-Tse Kao ◽  
...  
Keyword(s):  
Wear Resistance ◽  
Friction Coefficient ◽  
Ceramic Material ◽  
Glass Surface ◽  
Structural Changes ◽  
Tooth Enamel ◽  
Material Surface ◽  
Dental Ceramic ◽  
Adsorbed Protein ◽  
Wide Range

Dental ceramic material is one of the widely preferred restorative materials to mimic the natural tooth enamel surface. However, it has continuously been degraded because of low wear resistance during mastication in the oral cavity. The friction involved was reduced by introducing the lubricant saliva protein layers to improve the wear resistance of the dental materials. However, little is understood regarding how the protein–protein interactions (PPI) influence the adsorbed-state structures and lubricating behaviors of saliva proteins on the ceramic material surface. The objective of this study is to quantify the influences of PPI effects on the structural changes and corresponding oral lubrications of adsorbed α-amylase, one of the abundant proteins in the saliva, on the dental ceramic material with glass as a model surface. α-Amylase was first adsorbed to glass surface under varying protein solution concentrations to saturate the surface to vary the PPI effects over a wide range. The areal density of the adsorbed protein was measured as an indicator of the level of PPI effects within the layer, and these values were then correlated with the measurements of the adsorbed protein’s secondary structure and corresponding friction coefficient. The decreased friction coefficient value was an indicator of the lubricated surfaces with higher wear resistance. Our results indicate that PPI effects help stabilize the structure of α-amylase adsorbed on glass, and the correlation observed between the friction coefficient and the conformational state of adsorbed α-amylase was apparent. This study thus provides new molecular-level insights into how PPI influences the structure and lubricating behaviors of adsorbed protein, which is critical for the innovations of dental ceramic material designs with improved wear resistance.

scholarly journals Identification of in vivo CFTR conformations during biogenesis and upon misfolding by covalent protein painting (CPP)

2021 ◽  
Author(s):  
Sandra Pankow ◽  
Casimir Bamberger ◽  
Salvador Martínez-Bartolomé ◽  
Sung-Kyu Park ◽  
John R. Yates
Keyword(s):  
Cystic Fibrosis ◽  
Protein Interactions ◽  
Structural Changes ◽  
Solvent Accessibility ◽  
Protein Structures ◽  
Permissive Temperature ◽  
Intracellular Loop

AbstractIn vivo characterization of protein structures or protein structural changes after perturbation is a major challenge. Therefore, experiments to characterize protein structures are typically performed in vitro and with highly purified proteins or protein complexes. Using a novel low-resolution method named Covalent Protein Painting (CPP) that allows the characterization of protein conformations in vivo, we are the first to report how an ion channel, the Cystic Fibrosis Transmembrane Conductance Regulator (CFTR), is conformationally changed during biogenesis and channel opening in the cell. Our study led to the identification of a novel opening mechanism for CFTR by revealing that the interaction of the intracellular loop 2 (ICL2) with the nucleotide binding domain 2 (NDB2) of CFTR is needed for channel gating, and this interaction occurs concomitantly with changes to the narrow part of the pore and the walker A lysine in NBD1. However, the ICL2:NBD2 interface, which forms a “ball-in-a-socket” motif, is uncoupled during biogenesis, likely to prevent inadvertent channel activation during transport. In particular, solvent accessibility of lysine 273 (K273) in ICL2 changes with the opening and closing of the channel. Mutation of K273 severely impaired CFTR biogenesis and led to accumulation of CFTR in the Golgi and TGN. CPP further revealed that, even upon treatment with current approved drugs or at permissive temperature, the uncoupled state of ICL2 is a prominent feature of the misfolded CFTR mutants ΔF508 and N1303K that cause Cystic Fibrosis (CF), which suggests that stabilization of this interface could produce a more efficient CF drug. CPP is able to characterize a protein in its native environment and measure the effect of complex PTMs and protein interactions on protein structure, making it broadly applicable and invaluable for the development of new therapies.

Optimum Infinite is a new era of oxygen permeability material for contact lenses

The Eye ◽  
2020 ◽  
Vol 22 (129) ◽  
pp. 44-46
Author(s):  
Mark Eddleston
Keyword(s):  
Contact Lens ◽  
Oxygen Permeability ◽  
Contact Lenses ◽  
New Era ◽  
Lens Material ◽  
Insight Into

Optimum Infinite is a new GP contact lens material, with an oxygen permeability of 180 barrer and was launched by Contamac at the GSLS 2019. This article provides an insight into the development and characteristics of this breakthrough material.

Probing the 14-3-3 Isoform-Specificity Profile of Interactions Stabilized by Fusicoccin A

2020 ◽  
Author(s):  
James Frederich ◽  
Ananya Sengupta ◽  
Josue Liriano ◽  
Ewa A. Bienkiewicz ◽  
Brian G. Miller
Keyword(s):  
Protein Interactions ◽  
Neurological Diseases ◽  
Adapter Proteins ◽  
Protein Protein Interactions ◽  
Specific Expression ◽  
Individual Client ◽  
Isoform Specificity ◽  
Fusicoccin A

Fusicoccin A (FC) is a fungal phytotoxin that stabilizes protein–protein interactions (PPIs) between 14-3-3 adapter proteins and their phosphoprotein interaction partners. In recent years, FC has emerged as an important chemical probe of human 14-3-3 PPIs implicated in cancer and neurological diseases. These previous studies have established the structural requirements for FC-induced stabilization of 14-3-3·client phosphoprotein complexes; however, the effect of different 14-3-3 isoforms on FC activity has not been systematically explored. This is a relevant question for the continued development of FC variants because there are seven distinct isoforms of 14-3-3 in humans. Despite their remarkable sequence and structural similarities, a growing body of experimental evidence supports both tissue-specific expression of 14-3-3 isoforms and isoform-specific functions <i>in vivo</i>. Herein, we report the isoform-specificity profile of FC <i>in vitro</i>using recombinant human 14-3-3 isoforms and a focused library of fluorescein-labeled hexaphosphopeptides mimicking the C-terminal 14-3-3 recognition domains of client phosphoproteins targeted by FC in cell culture. Our results reveal modest isoform preferences for individual client phospholigands and demonstrate that FC differentially stabilizes PPIs involving 14-3-3s. Together, these data provide strong motivation for the development of non-natural FC variants with enhanced selectivity for individual 14-3-3 isoforms.

Discovery of New AKT1 Inhibitors by Combination of In silico Structure Based Virtual Screening Approaches and Biological Evaluations

2019 ◽  
Author(s):  
Filip Fratev ◽  
Denisse A. Gutierrez ◽  
Renato J. Aguilera ◽  
suman sirimulla
Keyword(s):  
Virtual Screening ◽  
Success Rate ◽  
Protein Interactions ◽  
In Silico ◽  
Biological Data ◽  
In Vitro Binding ◽  
Vitro Binding ◽  
Screening Protocol ◽  
Screening Approaches

AKT1 is emerging as a useful target for treating cancer. Herein, we discovered a new set of ligands that inhibit the AKT1, as shown by in vitro binding and cell line studies, using a newly designed virtual screening protocol that combines structure-based pharmacophore and docking screens. Taking together with the biological data, the combination of structure based pharamcophore and docking methods demonstrated reasonable success rate in identifying new inhibitors (60-70%) proving the success of aforementioned approach. A detail analysis of the ligand-protein interactions was performed explaining observed activities.<br>

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